This invention generally relates to lumbar support systems for automotive vehicles. More particularly, the present invention relates to lumbar support device in the form of an energy-absorbent, high density foam insert for attachment to a vehicle seat in the approximate region of the lumbar curvature of the human spine.
Materials for vehicle interiors, particularly vehicle seats, have had a long history of development. Vehicle seats were formed from leather over padding. Eventually the padding was supported by an array of coil springs attached at one end to a wooden supporting frame. The padding for early vehicle seats was selected from a natural material such as horse hair and cotton. Eventually, synthetic materials replaced the natural materials due largely to cost and comfort considerations. The synthetic material of choice was a polyurethane foam, and most seat bodies have been made ever since from such material.
Today, in the design and manufacture of seats for vehicles, particularly automotive vehicles, both safety and comfort are areas of greater concern. In the area of safety, it is increasingly desired to eliminate seat rebound in the event of a rear-end collision. The goal in such design is to have the seat absorb impact energy so that the seat does not re-deliver the energy (much like a spring) to the occupant during a re-bound phase.
Some efforts have been made with varying degrees of success to respond to this need. For example, attention may be directed to U.S. Pat. No. 5,290,089, issued to Oleszko et al. on Mar. 1, 1994, for SEAT BELLOWS ENERGY ABSORBER which discloses a recliner arrangement for a vehicle seat that includes an energy absorber positioned between a linear recliner element and a seat backrest unit. The energy absorber is operative upon a force exerted thereon. Attention may also be directed to U.S. Pat. No. 5,310,030, issued to Kawakita et al. on May 10, 1994, for ENERGY-ABSORBING FASTENED STRUCTURE which discloses an energy-absorbing fastened structure for use with a vehicle seat. The structure includes first and second platelike members fastened by a fastener. Finally, attention may be directed to U.S. Pat. No. 5,836,647, issued to Turman on Nov. 17, 1998, for VEHICLE SEAT WITH SHOCK ABSORPTION which includes a rear impact energy absorbing damping system. Each of these disclosures relates to a method of absorbing energy from a vehicle impact.
In addition to seeking an improvement in the design of the automotive vehicle seat to improve safety, automobile designers are also continuously interested in improving seat comfort. Much energy has been devoted to the improvement of a vehicle seat which provides improved support and comfort for the driver""s back. Particularly, attention has been devoted to providing support for the driver""s lumbar vertebrae which include the lowermost five vertebra of the human vertebral column. The lumbar vertebrae are frequently subjected to a high degree of downward pressure, a condition which frequently leads to the non-life threatening (but endlessly annoying) condition known commonly as xe2x80x9clower back pain.xe2x80x9d
Many efforts have been undertaken to deal with this condition. For example, some vehicle seats have been fitted with an inflatable air bladder situated roughly behind the lumbar region of the driver""s back. By toggling a control switch, the driver can control the amount of air pumped into (or released from) the air bladder. An example of such a device may be found in U.S. Pat. No. 5,967,608, issued to Van Sicle on Oct. 19, 1999, for PNEUMATIC LUMBAR ADJUSTMENT SYSTEM.
Other attempts have been known at providing lumbar support for vehicle seats. For example, U.S. Pat. No. 5,911,477, issued on Jun. 15, 1999, to Mundell et al. for LUMBAR SUPPORT STRUCTURE FOR AUTOMOTIVE VEHICLE discloses a lumbar support mechanism for incorporation into a seat. The mechanism comprises a pair of opposing triangular brackets, each having a base and a peak, wherein the brackets are positioned such that the peaks are facing one another. The brackets are movable with respect to each other. An additional example of a lumbar support device may be found in U.S. Pat. No. 5,947,558, issued to Suzuki et al. on Sep. 7, 1999, for LUMBAR SUPPORT DEVICE. The device of this patent includes a first drive device fixed to a stationary bracket member to move a lumbar pad upward and downward of a seat back, and a second drive device secured on a movable member which is one member of a link mechanism.
While arguable providing improvements in the areas of safety and comfort, no satisfactory approach to resolving both of these concerns has been advanced, thus a resolution to the need for providing safety and comfort for the lower back of the driver seated in a vehicle remains wanting.
It is an object of the present invention to provide a seat for a vehicle, particularly an automotive vehicle, which overcomes the above problems.
More particularly, it is an object of the present invention to provide an insert for attachment to a vehicle seat to provide passive support to the lumbar region of the human spine.
It is a further object of the present invention to provide such a seat insert which, when combined with a vehicle seat, offers improved comfort over known vehicle seats.
A further object of the present invention is to provide such a seat insert which is composed of a high-density, semi-rigid material.
Still a further object of the present invention is to provide such a seat insert which is composed of a polyurethane.
Yet an additional object of the present invention is to provide such a seat insert which is composed of one or more materials selected from the group consisting of polyethylene, polypropylene, and polystyrene.
An additional object of the present invention is to provide such a seat insert which is composed of two or more layers of different polymerized materials.
Still a further object of the present invention is to provide such seat insert which is formed in accordance with a mold of a driver""s back.
Yet still an additional object of the present invention is to provide such a seat insert which is attached to the seat back by chemical or mechanical attachment.
These and other advantages are achieved by the provision of an energy absorbing seat insert for a vehicle seat. The seat insert provides support for the user""s lumbar area. The insert is preferably composed of high-density, energy absorbing polymerized material such as a polyurethane. Alternatively, the insert may be composed from other polymerized materials, including polyethylene, polypropylene, and polystyrene, or any combination thereof. The insert may be made of a single polymer or a mixture, or may be composed of multiple layers of two or more different polymers. Attachment of the insert to the seat back may be accomplished by chemical or mechanical fastening. The insert may be molded to conform to the profile of the lumbar region of the back of a particular driver.